Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: FAT32 superiority over ext2 :-) | Date | Mon, 25 Jun 2001 01:22:17 +0200 |
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On Monday 25 June 2001 00:54, Albert D. Cahalan wrote: > By dumb luck (?), FAT32 is compatible with the phase-tree algorithm > as seen in Tux2. This means it offers full data integrity. > Yep, it whips your typical journalling filesystem. Look at what > we have in the superblock (boot sector): > > __u32 fat32_length; /* sectors/FAT */ > __u16 flags; /* bit 8: fat mirroring, low 4: active fat */ > __u8 version[2]; /* major, minor filesystem version */ > __u32 root_cluster; /* first cluster in root directory */ > __u16 info_sector; /* filesystem info sector */ > > All in one atomic write, one can... > > 1. change the active FAT > 2. change the root directory > 3. change the free space count > > That's enough to atomically move from one phase to the next. > You create new directories in the free space, and make FAT > changes to an inactive FAT copy. Then you write the superblock > to atomically transition to the next phase.
Yes, FAT is what inspired me to go develop the algorithm. However, two words: 'lost clusters'. Now that may just be an implemenation detail ;-)
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